Authentication system and method, identification information inputting method and apparatus and portable terminal

ABSTRACT

An authentication system in which unauthorized acquisition of the private information by a third party in the course of authentication of a user by a service provider is rendered difficult. In an authentication system in which a card  10  and a host computer  20  are interconnected over a connection line  30 , the card  10  includes a memory for ID  11  for storing the card ID, an input unit  12  fed with a secret identification number, a card side interface  13  connected to the host computer  20 , an information encryption unit  14  for generating the information for authentication by mixing a random number, sent from the host computer  20  and having a unique value each time it is sent, with the secret identification number of the card, and by encoding the resulting mixed signal, and a transient storage unit  15  for transiently storing the information for authentication as obtained by the information encryption unit  14.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of the patent application Ser. No. 10/082,186, filed Feb. 26, 2002, which claims priority from Japanese Application No.: 2001-052770, filed Feb. 27, 2001, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an authentication system and method, an identification information inputting method and apparatus and portable terminal. More particularly, it relates to an authentication system and method which, in the process of a service provider authenticating a user, render unauthorized acquisition of the personal information on the user by a third party difficult. This invention also relates to an identification information inputting method and apparatus and a portable terminal which, in the process of a user inputting an encryption key, render unauthorized acquisition of the personal information on the user by a third party difficult.

2. Description of Related Art

Heretofore, in recognizing whether or not a user is authorized to exploit a given service entity, a method has basically been used in which a service provider issues a physical ticket or a member's card for the user in advance and, at the point in time of the user exploiting the service, the ticket or the member's card is checked by way of performing the authentication.

For example, in a credit sale system, typified by a credit card sale system, the service provider identifies a user by the card information recorded on a card presented by the user, that is the personal information, in order to carry out credit trading. In this case, the user is authenticated by simply causing a card reader to read the credit card owned by the user.

On the other hand, a so-called debit payment system in which the debit has the opposite meaning to that of credit is also becoming accepted as being among the various payment methods. In the debit payment service, a user inserts a bank cashing card in a sale point information management terminal, or point-of-sale (POS) terminal, and enters a secret identification number and amount. In this case, the charge is instantly transferred from the user's account by way of performing a liquidation.

Also, with the coming into widespread use of the Internet, a user is able to purchase goods through the Internet and to make corresponding payments. For example, the user is able to make payment on simply transmitting the preset information of a credit card to the service provider.

The present Assignee has already proposed encrypting a key signal using a random number for preventing unauthorized use (Japanese Laying-Open Patent Publication 2000-332748).

However, the above-described payment methods are low in reliability for an authentication procedure, such that acquisition by a third party of the card information may occur at any point in time in the process of the authentication procedure.

For example, the authentication procedure by a credit card simply resides in causing the card reader to read-in the card. When shopping in a store and using a credit card for payment, the user hands his or her credit card to a sales clerk for payment procedure. At this time, the sale clerk is able to cause another card reader capable of holding the credit card information, to read-in the card information while being able to exchange willfully the card with another one. That is, the risk is high that the personal information stored in the card may be illicitly acquired (skimmed) by a third party.

In the case of the Internet, in particular, it may be a frequent occurrence that payment may be finished simply by the user transmitting the preset information stated on the credit card to the service provider. Up to now, there was the risk that the credit card information could be intercepted and stolen by a third party in the communication process. Moreover, in the case of the Internet, there is no direct contact between the service provider and the user, so that there is the risk that a third party could feign being the card owner in the communication process for payment and make an unauthorized false payment or could adulterate payment data, thus lowering reliability.

Also, in debit payment, a caching card is inserted into a POS terminal. Since the user inputs a secret identification number via input means in the POS terminal, the number may be illicitly acquired by a third party in the case where the input means, etc., of the POS terminal is willfully modified. On the other hand, should there be no physical screening means around the POS inputting means, the third party may be in a position to acquire illicitly the secret identification number by simply and secretly peeping at the figures of the numbers being input by the user. Moreover, if the secret identification number is skimmed, stolen or exchanged with another one, there is the risk that the card can be repeatedly used in an unauthorized manner until this state is recognized by the card owner.

Although there is known a technique of encrypting the key number by a random number, as described in the aforementioned Japanese Laying-Open Patent Publication 2000-332748, there is not a service system that is improved so that skimming of the secret identification number of the card may be prevented.

The above-described servicing system suffers from many drawbacks in connection with reliability, such that, if this problem is seen in the perspective of a business, the user may feel anxious about its safe service utilization due to this flaw in operational reliability. As a result, the number of users may not increase as expected, despite the fact that large installment investment is needed for POS equipment, thus leading to low profitability for the business.

In view of the above-described prior art technique, it is an object of the present invention to provide an authentication system and method which, in the process of the service provider authenticating a user, render it difficult for a third party to acquire illicitly the user's personal information.

It is another object of the present invention to provide an identification information inputting method and apparatus which, in the process of the user inputting the identification information, render it difficult for a third party to acquire illicitly the user's personal information.

It is still another object of the present invention to provide a portable terminal which, in the course of the user inputting identification information, renders it difficult for a third party to acquire illicitly the user's personal information.

It is a further object of the present invention to provide an authentication system and method, an identification information inputting method and apparatus and a portable terminal which remove the marked apprehension entertained by users at large about service exploitation, increase the number of latent users and improve the profitability of business.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides an authentication system made up by a portable terminal and an authentication device provided independently of the portable terminal for communication with the portable terminal. The authentication system includes first identification information storage means having the first identification information pre-stored therein for discriminating the portable terminal, operating means for inputting the second identification information associated with the first identification information, encryption means for encrypting the second identification information input by the operating means based on the preset encryption key generating information, and first communication means for communication with the authentication device. The authentication device includes second identification information storage means for storage of the first identification information and the second identification information therein, encryption key generating means for generating the encryption key generating information, second communication means for communication with the portable terminal and comparator authentication means for comparing the second identification information encrypted by the encryption means to the encryption key generating information by way of performing the authentication.

Preferably, the portable terminal encrypts the second identification information input from the operating means based on the encryption key generating information received from the authentication device through the first communication means, and the so encrypted second identification information is transmitted through the first communication means to the authentication device. In the authentication device, the encrypted second identification information received through the second communication means and the second identification information stored by the second identification information storage means are compared to the encryption key generating information by way of performing the authentication.

With the authentication system of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the authentication system of the present invention is applied to a credit sale system and to an inter-account instant payment carried out over the dedicated network or to E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string.

Moreover, with the authentication system according to the present invention, since the marked apprehension entertained by users at large about the reliability in card exploitation may be removed, the number of users of the credit sale system employing a card, an inter-account instant payment system employing a cash card, and E-commerce carried out over an optional network, such as the Internet, may be increased, thus enlarging the market while improving the profitability of business.

In another aspect, the present invention provides an authentication method which includes an operating step of inputting the second identification information associated with the first identification information for discriminating a portable terminal, pre-stored in first identification information storage means, an encryption key generating information generating step of generating the encryption key generating information, an encrypting step of encrypting the second identification information input at the operating step, based on the encryption key generating information generated in the encryption key generating information generating step, and a comparison authentication step of comparing the second identification information encrypted in the encrypting step based on the encryption key generating information and performing the authentication.

With the present authentication method, the second identification information input in the operating step is encrypted in the encrypting process based on the encryption key generating information. The so-encrypted second identification information is compared to the second identification information stored in the second identification information storage means and performs the authentication.

With the authentication method of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the authentication method of the present invention is applied to a credit sale system and to an inter-account instant payment carried out over the dedicated network or to the E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string.

Moreover, with the authentication method according to the present invention, since the marked apprehension entertained by users at large about the reliability in card exploitation may be removed, the number of latent users of a credit sale system employing a card, an inter-account instant payment system employing a cash card, and E-commerce carried out over an optional network, such as the Internet, is increased, thus enlarging the market while improving the profitability of business.

In another aspect, the present invention provides an identification information inputting device in which a string of a preset number of letters comprised of a combination of letters included in a preset group of letters is a letter string for authentication. The device includes display means for irregularly displaying the letter included in the preset group of letters, and selection means for selecting the letter string for authentication from among the letters irregularly displayed on the display means.

In the present identification information inputting device, the letters forming the letter string for authentication are selected in the selection means from among the letters included in the preset group of letters irregularly displayed on the display means.

In the above identification information inputting device, the letters making up the letter string for authentication are selected by selection means from among the letters included in the group of letters irregularly displayed in the display means.

With the above identification information inputting device of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the identification information inputting device of the present invention is applied to a credit sale system and to an inter-account instant payment carried out over the dedicated network or to the E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string for authentication.

Moreover, with the identification information inputting device according to the present invention, since the uneasiness entertained by users at large about the reliability in card exploitation may be removed, the number of users of the credit sale system employing a card, an inter-account instant payment system employing a cash card, and E-commerce carried out over an optional network, such as the Internet, is increased, thus enlarging the market while improving the profitability of business.

In another aspect, the present invention provides an identification information inputting method which includes a display step of irregularly displaying the letters included in the preset group of letters and a selection step of selecting the letter string for authentication from among the letters irregularly displayed in the display step.

In the present identification information inputting method, the letters forming the letter string for authentication are selected in the selection means from among the letters included in the preset group of letters irregularly displayed on the display means.

With the identification information inputting method of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the identification information inputting method of the present invention is applied to a credit sale system and to an inter-account instant payment, carried out over the dedicated network or to the E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string for authentication.

Moreover, with the identification information inputting method according to the present invention, since the uneasiness entertained by users at large about the reliability in card exploitation may be removed, the number of latent users of the credit sale system employing a card, an inter-account instant payment system employing a cash card, and E-commerce, carried out over an optional network, such as the Internet, is increased, thus enlarging the market while improving the profitability of business.

In another aspect, the present invention provides a portable terminal authenticated by an authentication device, including first identification information storage means having the first identification information for discriminating the portable terminal pre-stored therein, operating means for inputting the second identification information associated with the first identification information, communication means for communication with the authentication device and encrypting means for encrypting the second identification information input by the operating means based on preset encryption key generating information sent over the communication means from the authentication device.

In the present portable terminal, the second identification information associated with the first identification information input at the operating means is encrypted by the encrypting means based on the preset encryption key generating information sent over the communication means from the authentication device.

With the portable terminal of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the portable terminal of the present invention is applied to a credit sale system and to an inter-account instant payment carried out over the dedicated network, or to the E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string for authentication.

Moreover, with the portable terminal according to the present invention, since the uneasiness felt by users at large about the reliability in card exploitation may be removed, the number of users of the credit sale system employing a card, an inter-account instant payment system, employing a cash card, and E-commerce, carried out over an optional network, such as the Internet, is increased, thus enlarging the market while improving the profitability of business.

In yet another aspect, the present invention provides an authentication system made up by a portable terminal and an authentication device provided independently of the portable terminal for communication with the portable terminal. The authentication system includes first identification information storage means having the first identification information pre-stored therein for discriminating the portable terminal, operating means including display means for irregularly displaying letters included in a group of letters and selection means for selecting the letters making up the second identification information from among the letters irregularly displayed on the display means, the operating means inputting the second identification information associated with the first identification information, encryption means for encrypting the second identification information input by the operating means based on the preset encryption key generating information and first communication means for communication with the authentication device. The authentication device includes second identification information storage means having the first identification information and the second identification information stored therein, encryption key generating information generating means for generating the encryption key generating information, second communication means for communication with the portable terminal and comparator authentication means for comparing and authenticating the second identification information encrypted by the encryption means based on the encryption key generating information.

In the above authentication system, the portable terminal encrypts the second identification information input from the operating means based on the encryption key generating information received from the authentication device, and the so-encrypted second identification information is transmitted through the first communication means to the authentication device. In the authentication device, the encrypted second identification information received through the second communication means and the second identification information stored by the second identification information storage means are compared to the encryption key generating information and performing the authentication.

With the authentication system of the present invention, it is difficult for a third party to acquire the user's private information in an unauthorized fashion in the process until the service provider authenticates the user.

In particular, when the authentication system of the present invention is applied to a credit sale system and to an inter-account instant payment carried out over the dedicated network or to E-commerce carried out over an optional network, such as the Internet, it is possible to improve interception properties when the user inputs the secret identification number as a letter string for authentication.

Moreover, with the authentication system according to the present invention, since the uneasiness felt by users at large about the reliability in card exploitation may be removed, the number of latent users of the credit sale system employing a card, an inter-account instant payment system employing a cash card, and E-commerce, carried out over an optional network, such as the Internet, is increased, thus enlarging the market while improving the profitability of business.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating the progress of authentication of a portable terminal by an authentication device as an exemplary structure of the present invention.

FIG. 2 shows a structure of an authentication system as an exemplary structure of the present invention.

FIG. 3 shows another structure of an authentication system as an exemplary structure of the present invention.

FIG. 4 shows the appearance of a card as a portable terminal in an authentication system as an exemplary structure of a card as a portable terminal in an authentication system as an exemplary structure of the present invention.

FIG. 5 shows the appearance of another card as a portable terminal in an authentication system as an exemplary structure of a card as a portable terminal in an authentication system as an exemplary structure of the present invention.

FIG. 6 shows the appearance of a further card as a portable terminal in an authentication system as an exemplary structure of a card as a portable terminal in an authentication system as an exemplary structure of the present invention.

FIG. 7 is a schematic view showing the case of making payment for goods purchased with a card by a card owner in a store.

FIG. 8 is a schematic view showing the case of making payment by a card owner at a high class restaurant.

FIG. 9 is a schematic view showing the case of making payment by a card owner over the Internet via a network terminal such as a PC.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the rudimentary process for an authentication device to authenticate a portable terminal and its owner in an authentication system of the present invention.

When the owner of a portable terminal intends to receive preset services using a portable terminal, he or she inputs the second information to a portable terminal (step S1). The second identification information in this case is a string of letters, such as a secret identification number, accorded to the user of the portable terminal in association with the first identification information. This secret identification number, as the letter string for authentication, and the first identification information, as the identification information proper to the portable terminal, as later explained, are accorded from the service provider at the outset.

The portable terminal transmits the first identification information stored in the first identification information storage unit to the authentication device (step S2). The first information is the information indicating whether or not the portable terminal is being supervised; and is stored in a second identification information storage unit provided in the authentication device along with the string of letters for identifying the owner of the portable terminal.

When the authentication device acquires the first identification information from the portable terminal and ascertains that the portable terminal is being supervised by the authentication device, the authentication device at step S3 generates the information for encrypting the information (encryption key), such as a random number, and transmits the so-generated random number (step S3) to the portable terminal. The so-generated random number is associated with the first identification information of the portable terminal and provisionally (transiently) stored in the authentication device. This random number is used for encrypting and suppressing the letter string for authentication when the portable terminal sends the letter string for authentication to the authentication device. The letter string for authentication is encrypted at an encrypting unit of the portable terminal based on a preset rule. The rule for encryption may be prepared using pre-existing known encrypting methods. The portable terminal sends the encrypted letter string for authentication to the authentication device (step S4).

On receipt of the encrypted letter string for authentication from the portable terminal, the authentication device compares the letter string for authentication of the owner of the portable terminal stored in association with the first identification information in the second authentication information storage unit provided in the authentication device to the letter string for authentication transmitted encrypted from the portable terminal. When the letter string for authentication from the portable terminal coincides with the letter string for authentication stored in the second identification information storage unit of the authentication device, the person who entered the letter string for authentication at the portable terminal in question is authenticated as the true owner of the portable terminal (step S5).

The comparison of the letter string for authentication of the owner of the portable terminal stored in the second authentication information storage unit in association with the first identification information to the encrypted letter string for authentication is carried out by first decoding the encrypted letter string for authentication, using the random number for encryption stored provisionally (transiently) in the authentication device, and then comparing the decoded results to the letter string for authentication stored in the authentication device. Alternately, the above-described sequence of operations may be reversed, that is, the letter string for authentication stored in the authentication device may first be encrypted with the random number using the same rule as that used in the portable terminal, with the encrypted results then being compared to the encrypted letter string for authentication from the portable terminal.

By generating a random number each time an owner of a portable terminal intends to enjoy a preset service, and by performing encryption based on this random number, the encrypted letter string for authentication, transmitted from the portable terminal is represented at all times with different codes, thus improving suppression characteristics.

The portable terminal erases the stored letter string for authentication following the authentication by the authentication device. The authentication device executes preset processing for the authenticated portable terminal (step S6).

There is no particular limitation to the timing at which the portable terminal is connected to the authentication device. That is, the portable terminal may be connected to the authentication device as the letter string for authentication is first input, or the portable terminal may first be connected to the authentication device as a first step and transiently disconnected from and subsequently re-connected to the authentication device after inputting of the letter string for authentication.

In the authentication system of the present invention, the portable terminal is authenticated by the authentication device by the above-described processing. In the authentication system of the present invention, the portable terminal cannot be authenticated by itself by the authentication device, except if the letter string for authentication, such as secret identification number (letter or number), is input by the owner, so that the third party is not in a position to perform illicit acts using only the portable terminal. At any rate, high suppression characteristics are required when the owner inputs the letter string for authentication to the portable terminal.

To this end, the input unit in the authentication system of the present invention for inputting the letter string for authentication as the secret identification number is made up by a display section for irregularly displaying letters included in a preset group of letters, and a selection section for selecting letters making up the letter string for authentication from the letters displayed irregularly in the display section. For example, ten numerical figures from 0 to 9 are irregularly displayed at optional positions in the display section for the ten numerical figures of 0 to 9. Moreover, the portable terminal is improved in suppression characteristics because no letter string for authentication used for authentication with respect to the authentication device is held therein.

Thus, the authentication system according to the present invention is an authentication system in which, in the process until authentication of the portable terminal by the authentication device (service provider) when the authentication device verifies whether or not the portable terminal in question is managed by the authentication device, the act of illicit acquisition of the card information or the terminal information by a third party is rendered difficult.

In particular, in the authentication device according to the present invention, it is presupposed that when the user utilizes the credit transaction system employing the credit card or the debit payment service employing the bank's cashing card, the seller who sold a commodity to the service provider or the user authenticates the information of no one other than the user as recorded on the card presented by the user and carries out payment based on such authentication. Consequently, the portable terminal in the instant embodiment is indicated as being a ‘card’ pre-issued from the service provider to the user, while the service mainly indicates ‘payment’ at the time of purchasing the commodity.

In distinction from the card used for authenticating the user in this sort of conventional service, the card as the portable terminal has an input unit for inputting the letter string for authentication (secret identification number or secret identification letter) and an information encrypting unit for generating the information for authentication for a host computer based on the preset information encryption information. The information encrypting unit mixes (calculates) a random number and a card ID as the card authentication information pre-stored in the card itself together into a code to form the information for authentication for the host computer. The card input unit, as this portable terminal, has sufficient suppression characteristics for assuring safety when the user inputs the secret identification number.

In short, the card as the portable terminal needs to have input the secret identification number by the card owner, while the function proper to the card for commerce aimed at authentication is not performed with the card itself, such that the card is not authorized by an authentication device with merely a simplified operation of reading the card by a card reader, as in the case of the conventional card.

An authentication system 1 is hereinafter explained by referring to the drawings. In FIG. 2, the authentication system 1 is a system for authentication in which a card 10 and a host computer 20, as an authentication device, are interconnected over a connection line 30. When connected to the card 10, the host computer 20 verifies whether or not the card 10 is supervised by the host computer 20 and also acquires the personal information of the card owner stored in the card to authenticate the card 10 and its owner.

The connection line 30 is either a dedicated line for connecting the card to the host computer 20 or the so-called Internet constructed by interconnecting plural networks to form a large-scale network. There may be variegated configurations of interconnecting the card 10 to the host computer 20 over the connection line 30. For example, the host computer 20 may be provided with a connection terminal for connection to the card 10 and connected to the card by the connection terminal and a connection line. In this case, the connection terminal and the host computer 20 are interconnected over a cable or a radio path. The card and the connection terminal may be interconnected with a contact connection with a magnetic readout, the connection terminal, or a non-contact connection.

The card 10 is made up by a memory for ID 11 for storing the card ID equivalent to the aforementioned first identification information, an input unit 12 via which the card owner inputs the secret identification number as a letter string for authentication, and a card side interface 13 connected to the host computer 20 over the connection line 30. The card ID is the information required for identifying the card and pre-accorded by the service provider. This card ID does not indicate the direct information specifying no one other than the user. The input unit 12, fed with the secret identification number as the letter string for authentication, is constructed so that the secret identification number of the card owner will not be illicitly acquired by a third party. The details of the input unit 12 will be explained subsequently.

The card 10 also includes an information encryption unit 14, a transient storage unit 15 and a display unit 16. The information encryption unit 14 mixes (calculates) the random number, equivalent to the aforementioned preset encryption generating information, transmitted from the host computer 20 and which has an inherent value each time it is transmitted, and the card ID, as the identification number for the card, into a code to generate the information for authentication for the host computer 20. In the transient storage unit 15, there is transiently stored the secret identification number input from the input unit. The secret identification number stored in the transient storage unit 15 is erased each time the authentication comes to a close or every preset time interval. The display unit 16 may, for example, be a liquid crystal display device. On the display unit 16, there is displayed the information required for inputting by the input unit 12, as an example. A wide variety of encrypting methods may be used for encryption in the information encryption unit 14.

The above components of the card 10 are controlled comprehensively by a card controller 17 having a CPU (Central Processing Unit), a RAM (Random Access Memory) as a work area for the CPU, and a ROM (Read-Only Memory) for storing e.g., a program designed for carrying out variegated processing operations. The card reader 17 manages the control for transmitting the card ID and the information for authentication to the host computer 20 while erasing the secret identification number stored in the transient storage unit 15 when the letter string for authentication transmitted as the information for authentication is authenticated by the host computer 20. The card controller 17 also is able to erase the memory contents of the transient storage unit 15 at every preset time interval.

Thus, the card 10 encodes the secret identification number with encryption keys different from one communication event with the host computer 20 to another. Moreover, the input secret identification number is not held after the encoding within the card, so that, if the card is stolen by a third party, the card by itself is not authenticated by the host computer 20.

The host computer 20 includes a host side interface 21 connected to the card 10 over the connection line 30, a random number generator 22 generating random numbers, and a storage unit for card ID/letter string for authentication 23 for holding the card ID of the card 10 and the letter string for authentication issued for the card ID in association with each other. The host computer 20 also includes an information decoding unit 24 for decoding the information for authentication to extract the card authentication information and a comparator authentication unit for the decoded letter string for authentication 25 for comparing and authenticating the information for authentication obtained on mixing the random number and the card ID by the information encryption unit 14 in the card 10 and on encoding the resulting mixed signal based on the generated random number. These various components are comprehensively controlled by a host controller 26 having a CPU, a RAM as a work area of the CPU and a ROM for storage of programs, etc., used for carrying out variegated processing operations. The card ID/storage unit for letter string for authentication 23 is adapted for holding the random numbers generated in the random number generator 22 in association with the generated card ID.

It is sufficient if the random number generator 22 generates the encryption key by a preset function at a preset timing. For example, an encryption key generator also may be used in which the inherent value obtained each time by a preset function based on the information obtained from GPS (Global Positioning System) or clocks is used as an encryption key. The host controller 26 associates the card ID sent from the card with the random number issued for the card, in order to store the card ID and the random number transiently in the card ID/storage unit for letter string for authentication 23. The host controller 26 also controls the information decoding unit 24 to extract the card identification information from the information for authentication. In the case of authentication on comparison in the comparator authentication unit for the decoded letter string for authentication 25, the host controller 26 furnishes preset service to the card owner.

In the above-described authentication system 1, the comparison of the letter string for authentication of the owner of the portable terminal stored in the card ID/storage unit for letter string for authentication 23 in association with the card ID to the letter string for authentication encrypted by the information encryption unit 14 (information for authentication) is carried out by decoding the encrypted letter string for authentication (information for authentication) using random numbers transiently stored in the host computer 20 and by subsequently comparing the decoded result with the letter string for authentication stored in the card ID/storage unit for letter string for authentication 23. However, it also is possible to encrypt the letter string for authentication stored in the card ID/storage unit for letter string for authentication 23 under the same rule as that of encryption used in the card and to compare the result to the encrypted letter string for authentication from the card 10.

Specifically, the host computer 20 in the authentication system 1 includes a host side encryption unit 27 for encryption under the same rule as that of the information encryption unit 14 in place of the information decoding unit 24, while including a comparator authentication unit for the encoded letter string for authentication 28 in place of the comparator authentication unit for the decoded letter string for authentication 25, as shown in FIG. 3. By encrypting the letter string for authentication stored in the card ID/storage unit for letter string for authentication 23 under the same rule as that of the encoding carried out in the card 10, the information for authentication can be compared and authenticated without decoding the information for authentication.

The secret identification number is input from the owner in the input unit 12 of the card 10, as described above. To this end, sufficient suppression characteristics must be guaranteed in the input unit 12 against the third party when the owner inputs the secret identification number. FIGS. 4 to 6 show a specified embodiment of the input unit 12, which enables the secret identification number to be input with high suppression characteristics. Heretofore, in a host computer or a connection terminal for a host computer, the secret identification number is input from a fixed input unit. In this case, it is difficult to suppress the encryption key from a third party at the inputting time. Since the secret identification number can be input to the card, the card owner is able to input the secret identification number into the card 10 at an optional place. That is, the card owner is able to protect his or her secret identification number inputting scene from the eye of the third party. Consequently, the input unit 12 is able to secure confidentiality at the time of inputting the secret identification number.

FIG. 4 schematically shows the appearance of the card 10 provided with the input unit 12 shown as a first embodiment. In the card 10 shown in FIG. 4, the display unit 16 features the ten numerical figures irregular, in optional places of the display unit. The input unit 12 is provided with a contact inputting function of detecting the contacted position and of reflecting the position information in the input, and is provided in superimposition on corresponding positions of the display unit 16.

In FIG. 4, reference numerals, or FIGS. 7, 8, 4, 3, 1, 5, 0, 6, 2, C, 9 and E are demonstrated from the upper left end towards the right lower end of the display unit 16. At the next inputting event, the respective numerical figures are displayed at different positions of the display unit 16. In FIG. 4, C and E denote a selection button and an erasure button, respectively. When inputting the secret identification number, the card owner touches desired numerical figures irregularly displayed on the display unit 16 to enter the letter string representing the secret identification number. When the inputting is finished, the card owner presses the button C. Button E is used when the input numerical figure is to be corrected or when the letter string input as the secret identification number is to be erased.

When a preset numerical figure is demonstrated at a preset position on the display unit, the same position is acted on each time the card owner inputs the secret identification number. In such a case, as the card is used repeatedly, a problem is raised that the numerical figures used as the secret identification number become known to the third party due to wear and/or contamination of the input unit 12. Moreover, the secret identification number may become known by the movement of the finger pressing the numerical figure on the inputting site. However, in the case of the card 10 having the inputting unit, shown in FIG. 4, it is difficult for the numerical figures used as the secret identification number to become known to the third party due to wear, contamination of the input unit 12 or finger movement at the time of input.

Referring to FIG. 5, a second embodiment of the input unit 12 is now explained. In the card 10 shown in FIG. 5, the display unit 16 causes light emission in the numerical figures of 0 to 9 or their vicinity on the card surface to point to the respective numerical figures. The display unit 16 is, e.g., a light emitting means, such as an LED (Light Emitting Diode), and emits light to point to a preset numerical figure. The display unit 16 may sequentially emit light from 0 to 9, from 9 to 0, or irregularly. The light emitting time interval may be constant or varied

Although the input unit 12 has a selection button S and an erasure button E, the button of the input unit 12 used for selection is only the button S. Since each display unit 16 emits light sequentially or irregularly, it is sufficient if the card owner thrusts the selection button when the desired numerical figure is indicated. In such a case, since the same position is pressed at all times in selecting the letter string as the secret identification number, it is difficult for the numerical figures used as the secret identification number to become known to the third party due to wear, contamination or to finger movements at the time of input.

Referring to FIG. 6, a third embodiment of the input unit 12 is hereinafter explained. In the card 10 shown in FIG. 6, the display unit 16 features displaying one of ten numerical figures. The display unit 16 may display the ten numerical figures sequentially or irregularly. The user presses a selection button S of the input unit 12 when the desired numerical figure is displayed to select the desired numerical figure.

In this case, only one button is pressed at all times in selecting the numerical figures in the input unit 12, so that it is difficult for the numerical figures used as the secret identification number to become known to the third party due to wear, contamination or to finger movements at the time of input.

In the above-described three embodiments, the suppression properties at the time of inputting the secret identification number may be further raised by setting the angle of view of the display unit 16 to a narrow angle.

Meanwhile, the present invention features a card as a portable terminal having the function of inputting the secret identification number, so that there is no particular limitation to the encrypting method in the signal transmission/receipt between the card 10 and the host computer 20, such that currently available encryption principles, such as an open key encryption system, may be applied. As a typical encryption method, it may be contemplated to use a value obtained on computing and processing of a random number transmitted from the computer 20 as the authentication device to the card 10 and the secret identification number of the card 10 under a preset rule, as an encryption key of the card 10 for the host computer 20.

Specifically, a case in which a random number generated by the host computer 20 is a 20-digit figure, the secret identification number of the card 10 is a 4-digit figure, and a four-digit figure made up of the secret identification number and the random number is generated in the information encryption unit 14 of the card 10 as the information for authentication is now explained.

There are 20!, that is, approximately 4×10¹⁸ ways of re-arraying the 20 digit numerical figure sent from the host computer 20 to the card 10 into four sets of numerical figures each comprised of five digit numerical figures. In re-arraying the 20-digit figure into four sets each comprised of five digit numerical figures, such a rule may be adopted in which the first digit of the first five digit figure is the 19th digit figure of the 20-digit random number, the second digit of the first five digit figure is the third digit figure of the 20-digit random number, the third digit of the first five digit figure is the 17th digit figure of the 20-digit random number and the fourth digit of the first five digit figure is the fifth digit figure of the 20-digit random number, with the fifth digit of the first five digit figure being the 15th digit figure of the 20-digit random number.

Next, one digit of the secret identification number made up of four digit numerical figures is inserted into each of the four sets of the five digit numerical figures to create 6-digit numerical figures. It is determined at which of the six possible inserting positions the numerical figure is to be inserted. There are (10×6)⁴ different ways, that is, approximately 1.3×10⁷ different ways of inserting the numerical figures.

Here, four five-digit numerical figures are determined from the 20-digit random number and multiplied with the six-digit numerical figures prepared as described above. There are (10⁵)⁴, that is, 10²⁰, different ways of multiplication. By this multiplication, four sets of 11- or 12-digit numerical figures are obtained.

An optional one digit is extracted from the lower ten digits of the 11 or 12 digit numerical figures. The four numerical figures, extracted by carrying out the above operations on the four sets of the numerical figures are combined, and the resulting numerical figures are used as the four-digit information for authentication. There are 14 different ways of so combining the numerical figures.

Thus, even in the above-described extremely simple case, approximately 3.1×10⁴⁹ information for authentication may be obtained by mixing the 20-digit random number and the four-digit secret identification number. Moreover, since the numerical value to become the ultimate information for authentication is of four digits and is of a smaller value, it may be difficult to counter-reckon the respective numerical figures by several to scores of skimming operations, even though the above-described calculations for encryption should become exposed.

With the above-described input unit 12 of the authentication system 1 for the card 10, it is possible to improve the suppression properties at the time of inputting the secret identification number as the letter string for authentication by the user.

Referring to FIGS. 7 and 8, a specified instance of payment with the use of the above-described authentication system 1 is hereinafter explained. Referring to FIG. 7, the case of making payments for the commodity purchased by a card owner at a sale store using a card is explained. A card owner 50 selects a commodity at a store 51 (step 71). When the commodity to be purchased is determined and the card owner intends to make payments, the sale store 51 connects a dedicated network terminal 52 of, e.g., a personal computer (abbreviated to PC) to a card issuing company 53 (step 72) and transmits the information pertinent to commodity information (contents and the amount of the commodity) (step 73). The card owner 50 checks for the commodity information (contents and the amount of the commodity) on the commodity being purchased (step 74) to enter the secret identification number in the card 54 (step 75). The card 54 on which the secret identification number has been input, is connected to the dedicated network terminal 52 (step 76). At this time, the above-described payment process is executed. On completion of the payment, a payment end receipt is transmitted from the card issuing company 53 (step 77).

When the card owner inputs the secret identification number to the card, he or she is able to enter the secret identification number in a place outside the sight of a third party. Although the card 54 with the secret identification number entered thereto may be handed to and, thus, may be seen by, e.g., a sale clerk in the course of the payment, it is difficult for a third party to illicitly acquire the secret identification number from the trace of the inputting operations on the card. Even if the card is willfully exchanged, the encryption information is unique to each event of the transmission, so that the encryption information generated on encryption is invalid for any other communication event, and hence it is difficult for any third party to illicitly acquire the private information.

The case of a card owner making payments in a high-class restaurant using a card is explained with reference to FIG. 8. Although the payment at a high-class restaurant is here explained, it is assumed that, in the payment configuration shown in FIG. 8, the card 54 is transiently handed to a third party, such as a waiter 55. The card owner 50 confirms, e.g., the accounting specifications, presented by the waiter to enter an amount, such as tips (step 81). The card owner 50 also enters the secret identification number on the card 54 (step 82) and hands the card 54 along with the accounting specifications to the waiter (step 83). The waiter 55, who has received the card 54 from the card owner 50, connects the dedicated network terminal 52, such as a PC, installed in the sale store, here the high-class restaurant 51, to the card issuing company 53, to transmit the information pertinent to the commodity (information pertinent to the contents of the commodity and the amount) (step 84). The waiter then connects the card 54, handed by the card owner 50, to the network terminal 52 (step 85). The above-described payment process is now carried out (step 86). On completion of the payment, a receipt indicating payment completion is transmitted from the card issuing company 53 (step 87). The waiter 55 then returns the card 54 along with the receipt indicating the payment completion to the card owner 50 (step 88).

In this case, the card owner is again able the secret identification number on a card in a place outside the sight of a third party. Although the card 54 with the secret identification number entered thereto may be handed to and, thus, may be seen by, e.g., a sale clerk in the course of the payment, it is difficult for a third party to illicitly acquire the secret identification number from the trace of the past inputting operations left on the card. Even if the card is willfully exchanged, the encryption information is unique to each event of the transmission, such that the encryption information generated on encryption is invalid for any other communication event, and hence it is difficult for any third party to illicitly acquire the private information.

The case of a card owner making payments over the Internet using a card is now explained with reference to FIG. 9. It is assumed here that the terminal, such as a PC, connected to the Internet is provided with a readout device loaded with the card 54 and that is adapted to read out the card information. It is also assumed here that the card owner 50 uses the PC installed on his premises, however, the card owner also may use a PC installed a store and that is connected to the Internet. The card owner 50 selects the commodities sold by the sale store 51, on the Internet through a network terminal 56, such as a PC, connected to the Internet (step 91). The card owner 50 then selects the card issuing company from whom the services to the card owner are offered (step 92). The card owner 50 then transmits the commodity information (the information pertinent to the commodity contents and amount) (step 93). The commodity information also is transmitted from the store 51 to the card issuing company 53. The card owner 50 then confirms the commodity information (step 94). The card owner 50 inputs the encryption number to the card 54 (step 95). The above-described payment process is executed (step 96). The card issuing company 53 transmits the information indicating the completion of payment (step 97).

In this case, the card owner is again able to enter the secret identification number on a card in a place out of sight of a third party. Even though the PC is installed, e.g., at a store for use by a large number of users, some form of the private information may be left within the PC, and the private information may be intercepted in the course of the information transmission/reception over the Internet; however, the encryption information is unique to each event of the transmission, so that the encryption information generated on encryption is invalid for any other communication event and hence it is difficult for any third party to acquire illicitly the private information.

It may be seen from above that, in the case where the authentication system 1 as an illustrative structure of the present invention is applied to the credit sale system or an inter-account instant decision system, which is carried out over a dedicated network, the result is improved suppression properties on the occasion of a user inputting the secret identification number as the letter string for authentication. This removes anxiety from users at large about the reliability in card exploitation to increase the number of latent users of the credit sale system a card, an inter-account instant payment system, employing a cash card, and E-commerce carried out over an optional network, such as Internet, thus enlarging the market while improving the profitability of business.

It is to be noted that the present invention is not limited to the above-described embodiments, but it may be modified in a number of ways without departing from its scope. For example, although the portable terminal in the authentication system 1 shown as an illustrative structure of the present invention is a card having an encoding circuit, the portable terminal also may be a PDA (Personal Digital Assistant), a portable telephone set or a portable PC in place of the card. Similarly to the card information in a credit card or a debit card, the private information stored in the portable telephone set, PDA or the PC is information that is not to be leaked to a third party. The use of a portable terminal by a user in making payment may be envisioned readily, as exemplified by a user shopping in a certain store and making payments using the private information stored in his or her portable telephone set. In such a case, authentication may be carried out with an authentication device by the processing shown in FIG. 1.

Consequently, even in an authentication system employing a portable terminal other than a card, it is possible to render difficult the unauthorized acquisition by a third party of the terminal information or the private information in the course of the procedure up to the authentication of a user by a service provider. 

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 25. An encryption key inputting device in which a string of a preset number of letters comprised of a combination of letters included in a preset group of letters is a letter string for authentication, said device comprising: display means for irregularly displaying the letters included in said preset group of letters; and selection means for selecting said letter string for authentication from among the letters irregularly displayed on said display means.
 26. The encryption key inputting device according to claim 25 wherein said preset group of letters is ten numerical figures from 0 to
 9. 27. The encryption key inputting device according to claim 25 wherein said display means irregularly displays said numerical figures in optional positions in said display means.
 28. The encryption key inputting device according to claim 25 wherein said display means displays said numerical figures one-by-one in an irregular sequence.
 29. The encryption key inputting device according to claim 25 wherein said display means displays the pre-entered numerical figures of from 0 to 9 or the vicinity thereof by emitting light thereat to indicate respective numerical figures.
 30. An encryption key inputting method in which a string of a preset number of letters comprised of a combination of letters included in a preset group of letters is a letter string for authentication, said method comprising: a displaying step of irregularly displaying the letters included in said preset group of letters; and a selection step of selecting said letter string for authentication from among the letters irregularly displayed in said display step.
 31. The encryption key inputting method according to claim 30 wherein said preset group of letters is ten numerical figures from 0 to
 9. 32. The encryption key inputting method according to claim 30 wherein said display step irregularly displays said numerical figures in optional positions in said display step.
 33. The encryption key inputting method according to claim 30 wherein said display step displays said numerical figures one-by-one in an irregular sequence.
 34. The encryption key inputting method according to claim 30 wherein said display step displays the pre-entered numerical figures of from 0 to 9 or the vicinity thereof by emitting light thereat to indicate respective numerical figures.
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